Method of treating amytrophic lateral sclerosis using melatonin

ABSTRACT

The present invention relates to the treatment of amyotrophic lateral sclerosis (ALS) and/or the improvement of motor function in individuals in need of such improvement using a melatonin compound or a pharmaceutical salt of the melatonin compound.

BACKGROUND OF THE INVENTION Field of the Invention

[0001] The present invention relates to the treatment of amyotrophiclateral sclerosis (ALS), the improvement of motor function and/or theprevention of a loss thereof in individuals in need of suchimprovement/prevention.

DESCRIPTION OF THE BACKGROUND

[0002] Amyotrophic lateral sclerosis (ALS) is a fatal motor neurondisease, affecting both the first and second motoneuron. The progressionof ALS is characterized by a degeneration of motor neurons associatedwith a dramatic demyelination in the anterior horn of the spinal cord.The etiology is only partially understood. Of the 5-10% familial cases,20% carry a mutation of the superoxide dismutase 1 (SODI) gene. Such amutation is also present in 5% of the sporadic cases (Rowland New Engl JMed 2001:344:1688-1700).

[0003] Pathophysiologically, three major mechanisms are discussed inALS: (a) mutations of the SODI gene, causing a toxic gain of functionwith enhanced reactivity towards abnormal substrates (tyrosinenitration), along with an impaired ability to bind zinc leading to areduced antioxidant capacity; (b) mutations in neurofilament genes andoxidative modifications or hyperphosphorylation of cytoskeletal proteinsleading to selective motor axon degeneration; (c) excitotoxicity causedby increased cerebrospinal fluid glutamate levels together with a lossof excitatory amino acid transporters (Rowland New Engl J Med2001:344:1688-1700).

[0004] There is no promising treatment available to date. The onlycompound yielding borderline significance with respect to survival timeis RILUZOLE® (2-amino-6-(trifluoromethoxy) benzothiazole), anantiexcitotoxin (Rowland New Engl J Med 2001:344:1688-1700). As thecommon basis of cellular and extracellular alterations in ALS seems tobe oxidative stress mediated by reactive nitrogen/oxygen species, futureattempts of treatment might focus on antioxidant strategies involvingsuppression of nitric oxide (NO) synthase.

[0005] Accordingly, there remains a prominent need for new therapies forimproving or preventing the loss of motor function in such patients,such as ALS patients.

[0006] Melatonin and melatonin derivatives are known to obey and affectcircadian rhythms in mammals when secreted from the pineal gland duringthe night (Reiter Prog Clin Biol Res 1981: 59C: 223-233; Stokkan &Reiter J Pineal Res 1994: 16: 33-36; Petrie et al., BMJ 1989: 298:705-707). Based on these observations, melatonin is often used off theshelf for treating jet lag.

[0007] Melatonin is also well-known as an antioxidant in neuronal andnon-neuronal tissues (J. Pineal Res. 1994: 17:94-100 and Life Sci 1994:56:83-89). In fact, such antioxidant properties have been shown torescue dopamine neurons from damage in an experimental model system(Iacovitti et al Brain Res 1997: Sep 12: 768(1-2): 317-26, Melatoninrescues dopamine neurons from cell death in tissue culture models ofoxidative stress). In addition, melatonin (at doses of 100 μM) has beenshown to “counteract the in vitro destructive effects of NMDA orhypoxia/reperfusion by preventing accumulation of excessive freeradicals” (Cazeville et al Brain Res 1997:768(1-2): 120-124). From theseobservations of the antioxidant properties of melatonin have beenprescribed at 3 mg melatonin doses in the evening to ALSIMNI patients(Dr. Stanley Appel of the Baylor Clinic in Texas).

[0008] Melatonin and various melatonin derivatives have been describedas being useful for treating anoxic or ischemic brain injury (U.S. Pat.No. 5,700,828).

[0009] However, melatonin has not been assessed for its effects whenadministered episodically at night in high doses in ALS patients or inpatients with other related neurodegenerative disorders.

SUMMARY OF THE INVENTION

[0010] Accordingly, it is an object of the present invention to providea new method for treating ALS patients by using melatonin and melatoninderivatives.

[0011] It is also another object of the present invention to improvemotor function in patients in need thereof, for example, ALS patients byusing melatonin and melatonin derivatives.

[0012] It is another object of the present invention to provide aprophylactic treatment to individuals at risk of developing ALS orrelated motor neuron diseases.

[0013] A more complete appreciation of the invention and many of theattendant advantages thereof will be readily obtained as the samebecomes better understood by reference to the following detaileddescription when considered in connection with the accompanyingdrawings, wherein:

BRIEF DESCRIPTION OF THE DRAWINGS

[0014]FIG. 1 is a depiction of rotorod test data obtained from melatoninversus vehicle (solvent only) treated SODG93A mice (n=9-12 per group).Rotarod failure is defined to start when mice are no longer able to stayin the rotarod for more than 300 sec (=early disease state). The daysfrom that time point to death are significantly more in melatonin thanin vehicle treated mice.

[0015]FIG. 2 is a depiction of clinical score data obtained frommelatonin versus vehicle (solvent only) treated SODG93A mice (n=9-12 pergroup). Shown are days after score 1 (abnormal hindlimb reflex or tremorin at least one extremity or asymmetrical gait) to score 4 (endpointcriteria/death). The days from score 1 to death are significantly morein melatonin than in vehicle treated mice.

DETAILED DESCRIPTION OF INVENTION

[0016] Unless otherwise defined, all technical and scientific terms usedherein have the same meaning as commonly understood by one of ordinaryskill in the art. Although methods and materials similar or equivalentto those described herein can be used in the practice or testing of thepresent invention, suitable methods and materials are described herein.All publications, patent applications, patents, and other referencesmentioned herein are incorporated by reference in their entirety. Incase of conflict, the present specification, including definitions, willcontrol. In addition, the materials, methods, and examples areillustrative only and are not intended to be limiting.

[0017] Patients who would benefit from the administration of melatonininclude ALS patients and patients with related motor neuron disease.

[0018] Since melatonin appears to be free from side effects even uponlong-term applications, melatonin can be used as a prophylaxis to treatthose patients that are at risk of developing ALS. Such patients wouldbe those that have been identified with the genetic marker associatedwith ALS, i.e., familial form of ALS, and those patients who exhibitearly signs of motor neuron disease, such as impaired motor control.

[0019] The treatment of those patients who would benefit from improvedmotor function are those with motor function loss that is a result of aparticular neurodegenerative disease, such as amyotrophic lateralsclerosis and other peripheral neuropathies.

[0020] The treatment protocol can also include administering to thepatients one or more additional agents that could improve motor functionor improve the overall disease outlook of the patient. For example,RILUZOLE® (2-amino-6-(trifluoromethoxy)benzothiazole), erythropoietincompounds (inclusive of erythropoietin analogues/derivatives such asthose described in U.S. Pat. Nos. 6,340,742, 5,547,933, 5,888,772, and5,856,298), magnesium, selen, creatine, amino acids, vitamins (forexample, vitamin A, C, D, and E), cannabinoids, estrogens, androgens,endothelins, orexins, GDNF, thrombopoietin and other growth factors suchas GM-CSF, G-CSF, and N-acetylserotonin and pinoline(6-methoxy-1,2,3,4-tetrahydro beta-carboline) (Reiter et al Adv Exp MedBiol 1999: 167: 379-387).

[0021] By “treating” is meant the slowing, interrupting, arresting orstopping of the progression of the disease or condition and does notnecessarily require the complete elimination of all disease symptoms andsigns. “Preventing” is intended to include the prophylaxis of theneurological disease, wherein “prophylaxis” is understood to be anydegree of inhibition of the time of onset or severity of signs orsymptoms of the disease or condition, including, but not limited to, thecomplete prevention of the disease or condition.

[0022] “Improving,” “Improvement,” or “Improved” as it relates to motorfunction is meant to mean any appreciable increase in motor function asmeasured using standard methodology known in the field.

[0023] Melatonin is a hormone, N-acetyl-5-methoxytryptamine, that isproduced by the pineal gland particularly during the evening becauseits' secretion is stimulated by the dark and inhibited by light.Melatonin is produced in a pathway where tryptophan in the pineal glandis converted to serotonin and ultimately melatonin (see also Bernard etal Reprod Nutr Dev 1999 May-Jun: 39(3):325-34). Melatonin has beenreported to have direct effects on circadian rhythms (Weaver et al. JClin Endocrinol Metab 1993: Feb 76(2):295-301).

[0024] Melatonin, in clinical use for many years, is well tolerated andsafe. Applications include altered day-night-cycle induced by shift workor jet lag, sleep induction and immune enhancement (Tan et al Curr TopMed Chem 2002: 2:181-197; Seabra et al J Pineal Res. 2000: 29:193-200).At present, melatonin is being tested in clinical trials for treatmentof Alzheimer disease because of its capacity to reduce in vitro Aβformation as well as aggregation and neurotoxicity (Reiter Prg.Neurobiol 1998; 56:359-384). The doses applied range from 1 to 2000 mg(short term) per day in cancer studies. Applications in humans arepredominantly oral (Seabra et al J Pineal Res. 2000: 29:193-200).

[0025] Melatonin has a unique broad spectrum of effects includingscavenging of hydroxyl, carbonate, alkoxyl, peroxyl and aryl cationradicals, stimulation of glutathione peroxidase and other protectiveenzymes, but also suppression of NO synthase. The interference with NOmetabolism has multiple consequences: down-regulation of NO formationcounteracts damage by peroxynitrite-dependent radicals as well asCa²⁺-dependent excitotoxicity. This pleiotropy may explain, at least inpart, why melatonin has been identified as a potent neuroprotectant,e.g., by attenuating oxidative damage after experimental neurotrauma(Reiter Prg Neurobiol 1998: 56:359-384; Tan et al Curr Top Med Chem2002: 2:181-197).

[0026] In addition, melatonin, because of its amphiphilicity, readilycrosses the blood-brain barrier (J. Pineal Res. 1988: 5:437-453).Although melatonin seems to have a rapid turnover, the administration ofslow release preparations maintains high plasma levels for about 6 hr.

[0027] In addition to melatonin, melatonin derivatives and melatoninanalogues are known in the art and may be employed in place of or incombination with melatonin itself (see U.S. Pat. No. 6,436,984; Faust etal J Med. Chem. 2000: 43(6):1050-1061; Gozzo et al Free Radic. Biol.Med. 1999: 26 (11-12):1538-1543; Hu et al Melanoma Res. 19988(3):205-210; Methe-Allainmat et al 1996: 39(16):3089-3095; Garratt etal J Med. Chem. 1996: 39(9):1797-1805). Collectively, melatonin,melatonin derivatives and melatonin analogues are termed melatonincompounds herein.

[0028] Melatonin may be administered as a pharmaceutically acceptablesalt, which include, but are not limited to, addition salts withinorganic acids or with organic acids. Compositions of melatonin used inthe invention may comprise, for example, at least one melatonin compoundin its free form, its pharmaceutically acceptable salt form, orcombinations of these.

[0029] A therapeutically effective amount of melatonin or dosage fortreating neurodegenerative diseases, such as ALS and peripheralneuropathies is an amount that results in at least an improved motorfunction and, preferably, an appreciable improvement in the overallhealth of the patient. For the purposes of the present invention such anamount is from about 30 to 600 mg of melatonin, inclusive of 30 to 60 mgand 300 to 600 mg which would relate to about 0.5 to about 10 mg/kg bodyweight and can be altered based on age, race, sex, and other factorsbased on the individual patient.

[0030] Melatonin can be formulated according to the mode ofadministration and combined with one or more various pharmaceuticallyacceptable carriers and/or excipients. The term “pharmaceuticallyacceptable” refers to molecules and compositions that arephysiologically tolerable and do not typically produce an allergic orsimilar unwanted reaction such as gastric upset or dizziness whenadministered. “Pharmaceutically acceptable” means approved by aregulatory agency of the Federal or a state government or listed in theU.S. Pharmacopoeia or other generally recognized pharmacopoeia for usein animals, preferably humans. The term “carrier” refers to a diluent,adjuvant, excipient, or vehicle with which the compound is administered.Such pharmaceutical carriers can be sterile liquids, such as salinesolutions, dextrose solutions, glycerol solutions, water, and oilsemulsions such as those made with oils of petroleum, animal, vegetable,or synthetic origin (peanut oil, soybean oil, mineral oil, or sesameoil). Water, saline solutions, dextrose solutions, and glycerolsolutions are preferably employed as carriers, particularly forinjectable solutions.

[0031] When melatonin is administered in a combination, it may bepremixed with additional compounds prior to administration, administeredsimultaneously, or administered in series. The route of administrationcan include the typical routes including, for example, orally,subcutaneously, transdermally, rectally, intravenously, intraarterially,by direct injection to the brain, and parenterally. Since patientssuffering from ALS have a loss of motor function, which includes adifficulty in swallowing, a preferred mode of administration is rectallyusing, for example, an enema, a suppository, and other similar deliveryvehicles.

[0032] In one aspect of the present invention, melatonin is administeredto the patients at night, e.g. just before the patient goes to sleep, toimitate an episodic release pattern with intervals aiming at maintenanceof the melatonin biorhythm. Based on this administration it may bepossible to prevent alterations in antioxidative enzyme systems and/ordevelopment of tolerance, i.e. loss of efficiency.

[0033] An exemplary administration is a suppository formulated tocontain not less than 300 mg of melatonin or a melatonin derivative,which is administered at night.

EXAMPLES Example 1

[0034] Three ALS patients with an estimated onset of disease 2-4 yrpreviously, were included in a pilot program in Göttingen, set up toexplore potential effects and side-effects of chronic high-dosemelatonin in this condition. Intraindividual follow-up (upon enteringthe study, and after 1, 2, 6, 9 and 13 months of treatment thus far)included physical examination/clinical rating scales (ALS functionalrating scale, ALSFRS), pulmonary function test, EMG-NCV, routinelaboratory parameters, psychological rating scales, as well as magneticresonance imaging and MR spectroscopy. Patients received 30-60 mg ofmelatonin as an oral slow release formulation in the late evening. Inaddition, they continued their “regular medication” in the morning andat noon (RIUZOLE® 50-100 mg, vitamins C and E, creatine, amitriptylin).

[0035] Melatonin was well tolerated over the entire observation period.No side effects have been reported or detected thus far. In particular,no signs of fatigue have been noted. The only problem identified to dateis that ALS patients, compromised in their swallowing function, have toswallow 10-20 melatonin tablets (slow release formulations of melatoninis available only in 3 mg tablets).

[0036] The clinical rating scales (ALSFRS) of the three patients fromthe start of the trial to one year later were: 34 to 22; 25 to 11; 31 to20, respectively. Whereas the patient with the most advanced state ofALS showed a progressive score decrease, two patients displayed anessentially stable score over time with an abrupt score drop at the lastexamination. Regarding the vital capacity of the lung, there was adistinctly reduced function (to less than 90%) already at the onset ofthis pilot study or in the early follow-up, respectively, indicatingrather advanced stages of the disease upon inclusion of the patients.Clinical laboratory parameters including complete blood cell count,sodium, potassium, calcium, magnesium, chloride, total protein, bloodglucose levels, triglycerides, total cholesterol, urea, creatinine,glutamic-oxalacetic transaminase, glutamic-pyruvate transaminase, GGT,GLDH, bilirubin, alkaline phosphatase, iron and c-reactive protein, didnot show alterations during melatonin treatment.

[0037] To conclude, this is the first study reporting on the chronicapplication of high-dose melatonin over more than 1 yr. It is notpossible to draw definitive conclusions on the efficacy of melatonin inthe treatment of ALS based on the present data. The high tolerability ofdaily oral melatonin in ALS patients, however, may encourage the use ofthis compound in a double-blind proof-of-concept trial.

Example 2

[0038] Using SODG93A-transgenic mice as an animal model for ALS, we wereable to show significant improvement in survival and course of disease,including several functional and behavioral parameters, e.g. rotarodperformance, progression of paresis or weight loss, upon high oralmelatonin treatment. No adverse effects of systemic melatonin wereobserved, even after application of several months. Melatonin wascontinuously applied via drinking water (0.5 mg/ml of water containing1% of ethanol to enable a saturated solution of melatonin) starting onday 28 of life and continued until death. The vehicle control receivedwater containing 1% of ethanol.

[0039] Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that within the scope of the appended claims, theinvention may be practiced otherwise than as specifically describedherein.

1. A method for the treatment of a patient suffering from amyotrophiclateral sclerosis, comprising administering at least one melatonincompound or a pharmaceutical salt thereof to the patient at night in anamount sufficient to treat the patient.
 2. The method of claim 1,wherein said administering comprises rectal administration.
 3. Themethod of claim 2, wherein said rectal administration comprisesadministering a suppository.
 4. The method of claim 1, wherein theamount sufficient to treat the patient is from 30 to 600 mg.
 5. Themethod of claim 1, wherein the amount sufficient to treat the patient isfrom 300 to 600 mg.
 6. The method of claim 1, wherein the melatonincompound is N-acetyl-5-methoxytryptamine or a pharmaceuticallyacceptable salt thereof.
 7. The method of claim 6, which furthercomprises administering 2-amino-6-(trifluoromethoxy) benzothiazole. 8.The method of claim 6, wherein the N-acetyl-5-methoxytryptamine or apharmaceutically acceptable salt thereof is administered rectally with asuppository.
 9. The method of claim 8, wherein the amount ofN-acetyl-5-methoxytryptamine or a pharmaceutically acceptable saltthereof is at least 300 mg.
 10. The method of claim 1, which furthercomprises administering at least one compound selected from the groupconsisting of 2-amino-6-(trifluoromethoxy)benzothiazole, anerythropoietin compound, magnesium, selen, creatine, an amino acid, avitamin, a cannabinoid, an estrogen, an androgen, endothelin, orexin,GDNF, thrombopoietin, a GM-CSF compound, a G-CSF compound,N-acetylserotonin, and 6-methoxy-1,2,3,4-tetrahydro beta-carboline. 11.The method of claim 10, wherein the compound is a vitamin.
 12. Themethod of claim 11, wherein the vitamin is at least one of vitamin A,vitamin C, vitamin D, and vitamin E.
 13. The method of claim 1, whereinthe administrating comprises a suppository with at least 300 mg of themelatonin compound.
 14. A method of improving motor function in apatient suffering from impaired motor function, comprising administeringat least one melatonin compound or a pharmaceutical salt thereof to thepatient in an amount sufficient to improve the motor function of thepatient relative to the motor function of the patient before theadministering.
 15. The method of claim 14, wherein said patient issuffering from amyotrophic lateral sclerosis.
 16. The method of claim14, wherein said administering comprises rectal administration.
 17. Themethod of claim 16, wherein said rectal administration comprisesadministering a suppository.
 18. The method of claim 14, wherein theamount sufficient to treat the patient is from 30 to 600 mg.
 19. Themethod of claim 14, wherein the amount sufficient to treat the patientis from 300 to 600 mg.
 20. The method of claim 14, wherein the melatonincompound is N-acetyl-5-methoxytryptamine or a pharmaceuticallyacceptable salt thereof.
 21. The method of claim 20, which furthercomprises administering 2-amino-6-(trifluoromethoxy) benzothiazole. 22.The method of claim 20, wherein the N-acetyl-5-methoxytryptamine or apharmaceutically acceptable salt thereof is administered rectally with asuppository.
 23. The method of claim 22, wherein the amount ofN-acetyl-5-methoxytryptamine or a pharmaceutically acceptable saltthereof is at least 300 mg.
 24. The method of claim 14, which furthercomprises administering at least one compound selected from the groupconsisting of 2-amino-6-(trifluoromethoxy) benzothiazole, anerythropoietin compound, magnesium, selen, creatine, an amino acid, avitamin, a cannabinoid, an estrogen, an androgen, endothelin, orexin,GDNF, thrombopoietin, a GM-CSF compound, a G-CSF compound,N-acetylserotonin, and 6-methoxy-1,2,3,4-tetrahydro beta-carboline. 25.The method of claim 24, wherein the compound is a vitamin.
 26. Themethod of claim 25, wherein the vitamin is at least one of vitamin A,vitamin C, vitamin D, and vitamin E.
 27. The method of claim 14, whereinthe administrating comprises a suppository with at least 300 mg of themelatonin compound.
 28. A method for the prophylactic treatment of anindividual at risk of developing amyotrophic lateral sclerosis,comprising administering at least one melatonin compound or apharmaceutically acceptable salt thereof to the individual in an amountsufficient to provide the prophylaxis for amyotrophic lateral sclerosis.29. The method of claim 28, wherein said administering comprises rectaladministration.
 30. The method of claim 29, wherein said rectaladministration comprises administering a suppository.
 31. The method ofclaim 28, wherein the amount sufficient to treat the patient is from 30to 600 mg.
 32. The method of claim 28, wherein the amount sufficient totreat the patient is from 300 to 600 mg.
 33. The method of claim 28,wherein the melatonin compound is N-acetyl-5-methoxytryptamine or apharmaceutically acceptable salt thereof.
 34. The method of claim 33,which further comprises administering 2-amino-6-(trifluoromethoxy)benzothiazole.
 35. The method of claim 33, wherein theN-acetyl-5-methoxytryptamine or a pharmaceutically acceptable saltthereof is administered rectally with a suppository.
 36. The method ofclaim 35, wherein the amount of N-acetyl-5-methoxytryptamine or apharmaceutically acceptable salt thereof is at least 300 mg.
 37. Themethod of claim 28, which further comprises administering at least onecompound selected from the group consisting of2-amino-6-(trifluoromethoxy) benzothiazole, an erythropoietin compound,magnesium, selen, creatine, an amino acid, a vitamin, a cannabinoid, anestrogen, an androgen, endothelin, orexin, GDNF, thrombopoietin, aGM-CSF compound, a G-CSF compound, N-acetylserotonin, and6-methoxy-1,2,3,4-tetrahydro beta-carboline.
 38. The method of claim 37,wherein the compound is a vitamin.
 39. The method of claim 38, whereinthe vitamin is at least one of vitamin A, vitamin C, vitamin D, andvitamin E.
 40. The method of claim 28, wherein the administratingcomprises a suppository with at least 300 mg of the melatonin compound.